Spreader stoker apparatus



Oct. 9, 1956 R. c. RIVERS ET AL 2,765,933

SPREADER STOKEIR APPARATUS Filed Jan. 19, 1952 3 Sheets-Sheet 1 INVENTOR5 Russ-Eu. C. IF/VERs ATTORNEY Oct. 9, 1956 R. c. RIVERS ETAL 2,765,933

SPREADER STOKER APPARATUS Filed Jan. 19, 1952 s Shee ts-Sheet 2 T i ii INVENTORS fPussaL C. /P/ VE/EJ W/4L/HM 5. Hsrwrr ATTORNEY Oct. 9, 1956 c, RNERS ETAL 2,765,933

SPREADER STOKER APPARATUS Filed Jan. 19, 1952 3 Sheets-Sheet 5 INVENTORS fiussflz. C. fax 5E5 A ORNEY known devices of this kind due to clogging of the coal tates 2,765,933 SPREADER STOKER APPARATUS Russell C. Rivers and William B. Hewitt, Worcester,

Mass., assignors to Riley Stoker Corporatiom'Worcester, Mass, acorporation of Massachusetts Application January 19, 1952,-Serial No. 267,289 Claims. (Cl. 214-18.22)

This invention relates generally to spreader stoker apparatus and more particularly to a rotary feeding mechanism which sprays solid fuel over a furnace grate.

Although spreader stokers have been known for many years, this type of fuel distributing apparatus has suffered from a number of disabilities which prevented the realization of the many advantages which spreader feeding of fuel offers. One difliculty experienced in previouslyis that the amount of coal, or other solid fuel, is projected into the furnace in spurts in the hopper. Even when a feeder is used, the coal sometimes packs or sticks in the feeder and introduces the coal into the distributing member erratically. Furthermore, the coal tends to cling to the so-called cut-off plate which constitutes the lower edge of the aperture in the furnace wall through which the coal is projected; this makes for further inaccuracy in the distribution of the coal over the grate. Another difiiculty often experienced in spreader stokers is that the fuel is not introduced from the feeder to the rotor in a manner such that the fuel falls onto the distributing blades of the rotor in an accurate, determinable way. These difiiculties and many others are obviated bythe present invention.

It is therefore an outstanding object of the invention to provide a spreader stoker which distributes solid fuel over a furnace grate at an even rate and in an even pattern.

It is a further object of the invention to provide a spreader stoker having a drum feeder which introduces fuel to the distributing rotor in accurate, equal increments.

Furthermore, it is an'object of the present invention to provide a spreader stoker in which a novel means is provided for determining the manner in which the fuel falls from the feeder onto the rotor.

In addition, it is an object of this invention to provide a spreader stoker apparatus in which coa-l does not accumulate on the cut-off plate.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

The character of the invention, however, may be best understood by reference to certain of its structural forms, as illustrated by the accompanying drawings in which:

Figure 1 is a side view of the apparatus of the invention,

Figure 2 is a sectional view taken on the line 22 of Figure 4 and looking in the direction of the arrows.

Figure 3 is a sectional view of the apparatus taken on the line 33 of Figure 2 looking in the direction of the arrows and with one half of the apparatus broken away for clarity of presentation.

Figure 4 is a sectional view of the apparatus taken on the line 4-4 of Figure 2 with the other half of the apparatus broken away.

Like reference characters denote similar parts in the several figures of the drawings.

Referring first to Figure l, the apparatus of the invention, generally designated by the reference character It), is shown as comprising a generally funnel-shapedhopper 11 and a distributor housing 12. The hopper is provided at its upper portion with an opening 13 which maybe atent Y 19 through bell cranks 24,

closed by means *of a slidably-mounted door 14. The upper portion of the hopper is adapted to be attached to a conduit, not shown,-extendinrg to a full storage bin, also not shown. The apparatus is adapted to be attached to the outer surface of the wall of a furnace with an open side 15 of the'distributor housing 12 overlying an opening in the furnace wall. Other elements of theapparatus evident in Figure 1 will be described fully hereinafter.

Referring next to Figure 2, the open side 15 'of'the distributor housing 12 is shown attached to thefront'wall 16 of a furnace and overlyingan opening 17 therein. Mounted in the hopper 11 and extending transversely thereof is a feeder drum 1%. The drum 1? is keyed to a shaft 19 rotatably mounted in the opposite sidesof the hopper. The drum is of generally hollow, cylindrical segmental surface. Two series of these pockets exist on'the surface of the drum in side-by-side relation, but'with the pockets of one series staggered relative'to the pockets of the other. The shaft 19 is rotated by connection to a shaft 21 which is parallel to shaft 19 and is similarly mounted in opposite sides of the distributor housingIZ. The shaft'21 is connected to a mechanism,. not shown, which is designed for imparting to it a rotative reciprocatory motion, but which V mechanism forms no part of the present invention. The mechanism is mounted in a housing 22, best shown in Figure 3, and is provided with an external adjustment'means'ZS for varying the amount of rotative displacement of the shaft 21. Theshaft 21 imparts a unidirectional rotative motion to the drumshaft links'25 and 26 andover-running clutches 2'7 and28.

A shaft 29 extends from oneside to the other of the hopper 12 in the upper portion thereof near ithe front edge of the opening 13. This shaft serves to support rotatably a release apron 39 whose weight. causes it to swing toward the 'drum and whose surface. is partly cylindrical for surface of the drum. Forwardly across. Resilient fingers 32 are fastened totheapron 3t) and these fingers rest on the shaft 31 and hold the apron in spaced relation to the drum. The shaft31-also carries the wiper .blades'33 of which one isv provided for. each series of pocketsZtl. The blades 33 are mounted ,rotatably on theshaft 31 and have a more or less L-shapedv crosssection with the weight so distributed that they would .naturally hang at least partly within the space occupied vby the drum. The free end of the blade is formed ina knifeedge 34 which is preferably armored with tungsten carbide or the like and is adapted to scrape along the surfaceof the drum, even within the .pockets2i).

Mounted in the lower-portion. of the hopperandqextending into the furnace opening 17 in the furnace-wall is a cut oif plate 36. The plate 36 is of hollow construction and has a plane surface 37 which faces upwardly and rearwardly into the furnace. Apertures 38 extend from the hollow interior of the plate to the surface 37 and a conduit-39 enters the lower portion oftheplate, for a purpose to be explained hereinafter.

A horizontal wall 4% extends rearwardlyoverthe-shaft 21 and is provided at its rearward edge -with a aVCItlCHl abutment 45 which is apertured to receivean elongated bolt 46 which is prevented :from moving. longitudinally by a nut 47, rotative-movement being.possible, however. Aztrajectory plate 49 is situated. in'the space between the horizontal wall 40' and the lower portion of the drum"18 and this plate- 49 is providedwith a c-ap-member48-hav- 3 ing an upper wall 50 which is tangential to the drum 18, and a face 51 which is inclined upwardly and forwardly toward the furnace. The rearward portion of the upper surface of the trajectory plate 49 is provided with an abutment 52 which has a threaded aperture cooperating with the bolt 46. A nut 53 is threaded on the extreme end of the bolt 46 to limit movement of the trajectory plate 49. A similar means 57 is provided for adjustably attachlog the cap member 48 to the trajectory plate 49.

The apparatus is provided with numerous access doors and is formed in sections for ease in clearing and adjustment. As has been described above, thehopper 11 and the distributor housing 12 are formed as separate units. A door 54 is provided in the housing 12 for access to the bolt 46 and adjustment of the trajectory plate. A door 55 is provided in the trough '42 to permit adjustment of the distributor blades 44. Furthermore, means is provided for water-cooling of the portions adjacent the furnace; for instance, the portion of the distributor housing adjacent the furnace Wall is of hollow construction to form a water passage 56.

In the operation of the apparatus, the fuel enters the hopper 11 through the opening 13, the door 14 being withdrawn for this purpose. The fuel flows over the drum and packs firmly about it, so that each pocket 20 is filled with fuel. The drum rotates counterclockwise, according to the aspect presented in Figure 2, and, as each pocket passes under the apron 30, the coal is leveled off thereby, whereupon each pocket contains the same amount of fuel. If a large piece of fuel or a piece of foreign matter, such as tramp iron, enters the hopper and strikes the apron, it will swing upwardly about its shaft 29 and permit the piece to pass onward. As each pocket is rotated to a downwardly-facing position, the fuel falls outwardly and downwardly. Any fuel which remains in the pocket, because of wetness or the like,

is removed by the knife-edge 34 of the scraper blade 33;

because of the peculiar suspension of the blade, it cams along the surface of the drum with sufficient pressure to clean all fuel from the pockets. Here again, a large piece of fuel or the like will swing the blade out of the way and thus will not jam the apparatus. The fuel falls from the pockets onto the cap member 48 and slides down the inclined face '51, the angle of inclination of which is selected so that such sliding will take place easily. The fuel slides down the face 51, onto the trajectory plate '49 and from there onto the distributor blades 44 where it is impelled into the furnace in the well known manner. The point in its rotation at which the rotor strikes the downwardly flowing stream of fuel is determinable by adjustment of the trajectory plate relative to the distributor blades by means of the bolt '46, and the adjustment of the cap member relative to the trajectory plate by the means 57; the proper position of the trajectory plate for best performance will depend on the size, hardness, or wetness of the fuel and similar factors. As each particle of fuel is struck by a distributor blade it is thrown into the furnace to be burned. At the same time air is admitted through the conduit 39 into the hollow interior of the cut-off plate 36 from which it passes through the apertures 38 in jets. These air jets project the lighter particles of fuel upwardly into the furnace for burning in suspension and they also prevent build-up of fuel and the like on the face of the cut-off plate because of the cooling effect; having a clean cut-ofl plate is, of course, important in obtaining proper fuel distribution.

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereof. It is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

1. A spreader stoker, comprising a distributor housing a hopper mounted over said distributor,

adapted to be mounted before a furnace wall opening, a hopper mounted over said housing, a drum rotatably mounted in said hopper, a release apron overlying said drum, a wiper blade bearing against the surface of said drum, a trajectory plate mounted under said drum, and a distributor rotatably mounted in said housing and underlying said trajectory plate, the trajectory plate being adjustable relative to the distributor.

2. A spreader stoker, comprising a distributor housing adapted to be mounted before a furnace wall opening, a hopper mounted over said housing, a drum rotatably mounted in said hopper, said drum being formed with pockets having surfaces approximating segments of circular cylinders, said pockets being formed in multiple series, each series of pockets extending completely around the drum and the pockets of one series being staggered with respect to the pockets of the other and a wiper blade pressed against the drum to slide along the surface of each pocket once during each revolution thereof.

3. A spreader stoker, comprising a distributor housing adapted to be mounted before a furnace wall opening, a hopper mounted over said housing, a drum rotatably mounted in said hopper and having a series of cylindrical pockets formed in its surface, and a wiper blade hingedly mounted in the hopper on an axis parallel to the axis of rotation of the drum, said wiper blade having a knifeedge adapted to bear against the surface of the drum and to earn therealong, the weight of the blade relative to the drum axis and the blade axis being such that the free hanging position of the blade would be at least partly Within the space occupied by the drum.

4. A spreader stoker, comprising a rotary distributor adapted to be mounted before a furnace wall opening, a drum rotatably mounted in said hopper and having a series of pockets formed in its surface, and a trajectory plate mounted to underlie said drum, said trajectory plate having a cap member with an inclined face at its forward portion adjustably mounted thereon, said trajectory plate being adjustable as to its position under the drum and over the distributor.

5. A spreader stoker, comprising a distributor housing adapted to be mounted before a furnace wall opening, a hopper mounted over said housing, a drum rotatably mounted in said hopper, said drum being formed with pockets having surfaces approximating segments of circular cylinders, said pockets being formed in two series, each series of pockets extending completely around the drum and the pockets of one series being staggered with respect to the pockets of the other, a release apron hing edly mounted in the hopper on an axis parallel to the axis of rotation of the drum, said apron overlying the drum and having a surface conforming generally to the surface of the drum and normally occupying a position closely adjacent thereto, the apron being capable of a swinging motion away from the drum, a wiper blade hingedly mounted in the hopper on an axis parallel to the axis of rotation of the drum, said wiper blade having a knife-edge adapted to bear against the surface of the drum and to cam therealong, the weight of the blade relative to the drum axis and the blade axis being such that the free-hanging position of the blade would be at least partly within the space occupied by the drum, an adjustable trajectory plate mounted under said drum and having a cap member with an inclined face at its forward position adjustably mounted thereon, a distributor shaft rotatably mounted in said housing, distributor blades mounted on said shaft.

References Cited in the file of this patent 

